Symmetrical vane pump apparatus and method

ABSTRACT

The invention relates to a vane cell pump ( 1 ) comprising an electrical drive unit with an electric motor and a motor shaft ( 6 ), a pump chamber ( 2 ) that connects to the electrical drive unit and has a pump ring ( 3 ), and also a rotor ( 4 ) that is arranged concentric to the motor shaft ( 6 ) within the pump chamber ( 2 ) and is in active connection with the motor shaft ( 6 ), wherein the rotor ( 4 ) has a number of guide slots ( 40 ) that extend inward from the outer circumference of the rotor and in each of which a vane ( 5 ) is arranged in a moveable manner with two vane ends ( 50, 51 ) opposite each other. The vane ends ( 50, 51 ) of each vane ( 5 ) have a mirror-symmetric design relative to the transverse center plane of the vane.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority through German Application No. 10 2009 056 008.4 filed Nov. 26, 2009 and Application No. PCT/EP2010/068183 filed on Nov. 25, 2010.

BACKGROUND

The present invention relates to a vane cell pump comprising an electrical drive unit with an electric motor and a motor shaft, a pump chamber that connects to the electrical drive unit and has a pump ring, and also a rotor that is arranged concentric to the motor shaft within the pump chamber and is in active connection with the motor shaft, wherein the rotor has a number of guide slots that extend inward from the outer circumference of the rotor and in each of which a vane is arranged in a moveable manner with two vane ends opposite each other.

Vane cell pumps of the type named above, which are also frequently called rotary vane pumps, are already known in various constructions from the prior art. Examples for vane cell pumps can be found in DE 100 24 699 A1, DE 199 36 644 B4, DE 10 2006 058 977 A1, DE 10 2006 058 978 A1, DE 10 2006 058 979 A1, and DE 10 2006 058 980 A1.

The vane cell pumps known from the prior art have an electrical drive unit with an electric motor and a motor shaft, a pump chamber that connects to the electrical drive unit, and also a rotor that is arranged concentric to the motor shaft within the pump chamber. On its side, the rotor has a number of guide slots that extend inward from the outer circumference of the rotor. Each of these guide slots is suitable for holding a vane. Each of the vanes that has two vane ends opposite each other is arranged so that it can move in one of the guide slots. The vanes form work cells of different sizes depending on their rotational position with the inner wall of the pump ring, the outer wall of the rotor, and possibly adjacent vanes.

In FIG. 1, a vane 5′ is shown as it is used in numerous vane cell pumps known from the prior art. The vane 5′ has a first vane end 50′ that runs along the inner wall of the pump ring of the pump chamber when the vane cell pump is operating and the rotor is rotating. The first vane end 50 has a beveled design and a contour profile consisting of a first contour section 501 oriented essentially orthogonal to the longitudinal axis of the vane and a second contour section 502 extending diagonal to the longitudinal axis of the vane and thus forming a chamfer. The contour profile of the first end 50′ is adapted to the run-in pattern of a vane 5′ after a few hours of operation. This feature is realized due to the assumption that “run-in” vanes 5′ deliver better pneumatic performance from the beginning than vanes that are not adapted from the beginning to this wear pattern, so that the typical adjustment of the position of the pump ring relative to the rotor leads to very reliable pressure values of the vane cell pump from the beginning. In the embodiment shown in FIG. 1, the vane 1 has two rounded edge regions 510, 511 on a second vane end 51′ that lies opposite the first vane end 50′, so that the vane 5′ can extend as far as possible into the corresponding guide slot of the rotor when the rotor is operating. The two rounded edge regions 510, 511 are adapted to the radii required there for an optimum stress profile in the rotor under a load.

One problem in this solution known from the prior art is that, under some circumstances during assembly, the vanes can be inserted into the corresponding guide slots of the rotor in an incorrect orientation—that is, with the first vane end inward and with the second vane end outward. This incorrect assembly can remain undetected during a test of the vane cell pump and can lead, for long-term operation and under some circumstances, to undesired noise generation or also to vane breakage.

SUMMARY OF THE INVENTION

This is where the present invention comes into play. The present invention is based on the task of disclosing a vane cell pump of the type named above in which the vanes are constructed so that they can be installed in the guide slots in a way that prevents incorrect installation.

This task is achieved by a vane cell pump comprising an electrical drive unit with an electric motor and a motor shaft, a pump chamber that connects to the electrical drive unit and has a pump ring, and also a rotor that is arranged concentric to the motor shaft within the pump chamber and is in active connection with the motor shaft, wherein the rotor has a number of guide slots that extend inward from the outer circumference of the rotor and in each of which a vane is arranged in a moveable manner with two vane ends opposite each other, the vane ends of each vane having a mirror-symmetric design relative to the transverse center plane of the vane. The dependent claims relate to advantageous refinements of the invention.

A vane cell pump according to the invention is characterized in that the vane ends of each vane have a mirror-symmetric design relative to the transverse center plane of the vane. The transverse center plane is understood to be the plane extending orthogonal to the longitudinal axis of the vane and passing through the center point of the vane. One special advantage of the solution corresponding to the invention consists in that incorrect orientation of the vanes during installation in the guide slots can be prevented. In other words, the vanes can be inserted into the corresponding guide slots either with the first vane end or with the second vane end leading. Thus, the vanes can no longer be installed incorrectly, which could lead, for long-term operation of the vane cell pump and under some circumstances, to undesired noise generation or also to vane breakage. In one advantageous embodiment, there is the possibility that the vane ends of each vane also have a mirror-symmetric design relative to the longitudinal center plane of the vane.

To further simplify the installation, in one embodiment there is the possibility that each vane has a mirror-symmetric design relative to the transverse center plane of the vane. In addition, in one preferred embodiment, each vane can have a mirror-symmetric design relative to the longitudinal center plane of the vane.

In one advantageous embodiment, it is proposed that the vane ends of the vanes have a curved design. Therefore, damage to the vanes can be prevented in an especially effective way when the vane cell pump is operating. Advantageously, the vane ends of the vanes can have a convex curved design.

In one embodiment, it is proposed that the pump ring has elliptical inner contours. Such elliptical inner contours of the pump ring with a correspondingly shaped inner wall have the advantage that, in the interior of the pump chamber, smaller work cells are produced with significantly shorter extension paths of the vanes for each half revolution in comparison with a pump ring with circular contours for each full revolution. It has been shown that elliptical inner contours of the pump ring are especially advantageous for the case of a symmetric form of the vane ends.

In one embodiment it is proposed that the each of the guide slots of the rotor has a base section whose width is greater than the width of the vanes. Advantageously, the base sections of the guide slots are rounded and adapted, in particular, to the contours of the two vane ends.

Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in more detail below with reference to the accompanying drawings. Shown are:

FIG. 1 shows a schematic, simplified side view of a vane known from the prior art for a vane cell pump.

FIG. 2 shows a section through a vane cell pump according to a preferred embodiment of the present invention.

FIG. 3 shows a schematic, simplified side view of a vane used in the vane cell pump according to FIG. 2.

DETAILED DESCRIPTION

The basic structural shape and the basic functional principle of a vane cell pump 1 made according to a preferred embodiment of the present invention are known from the prior art and will be explained in more detail below with reference to FIG. 2. The vane cell pump 1 (rotary vane pump) can be constructed, in particular, as a vacuum pump operating according to the so-called principle of positive displacement for generating a vacuum. The vane cell pump 1 comprises an electrical drive unit that is housed in a housing of the vane cell pump 1 and has an electric motor with a motor shaft 6. Air or another fluid medium is taken in via a fluid inlet channel and flows into a pump chamber 2 of the vane cell pump 1. After passing through the pump chamber 2, the air flows out through a fluid outlet channel of the vane cell pump 1. The pump chamber 2 comprises a base plate, a pump ring 3, and a cover plate. In this embodiment, the pump ring 3 has elliptical inner contours with a correspondingly shaped inner wall 31. In an alternative embodiment there is also the possibility that the pump ring 3 has circular inner contours.

In the interior of the pump chamber 2 there is a cylindrical rotor 4 in active connection with the motor shaft 6 of the drive unit. The rotor 4 has a number of guide slots 40, each of which is suitable for holding a vane 5. In this embodiment, the rotor 4 has a total of eight guide slots 40 that are distributed around the circumference of the rotor and that extend inward from the outer circumference of the rotor. Each of the vanes 5 is arranged so that it can move in one of the guide slots 40. The rotor 4 is driven by the motor shaft 6 of the electric motor when the vane cell pump 1 is operating and thus the rotor is set in rotation. As can be seen in FIG. 2, the vanes 5 form work cells of different sizes depending on their rotational position with the inner wall 30 of the pump ring 3, the outer wall 42 of the rotor 4, and possibly adjacent vanes 5.

With further reference to FIG. 3 it becomes clear that the vanes 5 that are used in the vane cell pump 1 presented here and that are inserted into the guide slots 40 have a mirror-symmetric design with respect to their transverse center plane Q. The transverse center plane Q is understood to be the plane extending orthogonal to the longitudinal axis of the vane 5 and passing through the center point of the vane. Each of the vanes 5 has two free vane ends 50, 51 that have identical shapes and a convex, outward-pointing curvature. Advantageously, the vanes 5 are also mirror-symmetric with respect to their respective longitudinal center planes. Alternatively, there is also the possibility that only the vane ends 50, 51 are mirror-symmetric with respect to the transverse center plane Q of the vane 5, as well as optionally also mirror-symmetric with respect to the longitudinal center plane of the vane 5. The especially symmetric shape of the vanes 5 or vane ends 50, 51 has the advantage that incorrect installation of the vanes 5 in the guide slots 40 of the rotor 4 can be ruled out, because, due to their symmetry, the vanes can be inserted into the corresponding guide slots 40 of the rotor 4 optionally either with the first vane end 50 or with the second vane end 51 leading. Because incorrect assembly of the vanes 5 in the guide slots 40 can be prevented, the present invention also does not have the problem that the vanes 5 produce, under some circumstances, disruptive noise during operation due to installation of these vanes in the “incorrect” orientation and also cannot be possibly damaged.

The guide slots 40 of the rotor 4 are likewise adapted to the shape of the vanes 5. In the interior of the rotor 4, each of the guide slots 40 has a base section 41 whose width is greater than the width of the vanes 5. As can be seen from FIG. 2, the base sections 41 of the guide slots 40 are rounded and adapted, in particular, to the contours of the two opposing vane ends 50, 51.

As various modifications could be made to the exemplary embodiments, as described above with reference to the corresponding illustrations, without departing from the scope of the invention, it is intended that all matter contained in the foregoing description and shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents.

REFERENCE LIST

-   1 Vane cell pump -   2 Pump chamber -   3 Pump ring -   4 Rotor -   5, 5′ Vane -   6 Motor shaft -   40 Guide slot -   41 Base section -   42 Outer wall -   50, 50′ First vane end -   51, 51′ Second vane end -   501 First contour section -   502 Second contour section -   510 First rounded edge region -   511 Second rounded edge region 

1-9. (canceled)
 10. A vane cell pump comprising: an electrical drive unit with an electric motor and a motor shaft; a pump chamber that connects to the electrical drive unit and has a pump ring; a rotor that is arranged concentric to the motor shaft within the pump chamber and is in active connection with the motor shaft; the rotor has a number of guide slots that extend inward from the outer circumference of the rotor and in each of which a vane is arranged in a moveable manner with two vane ends opposite each other; and the vane ends of each vane being symmetric relative to a transverse center plane of the vane.
 11. The vane cell pump according to claim 10; wherein the vane ends of each vane have a symmetric design relative to the longitudinal center plane of the vane.
 12. The vane cell pump according to claim 10; wherein each vane is symmetric relative to the transverse center plane of the vane.
 13. The vane cell pump according to claim 10; wherein each vane is symmetric relative to the longitudinal center plane of the vane.
 14. The vane cell pump according to claim 10; wherein the vane ends of the vanes are curved.
 15. The vane cell pump according to claim 10; wherein the vane ends of the vanes are convex.
 16. The vane cell pump according to claim 10; wherein the pump ring has elliptical inner contours.
 17. The vane cell pump according to claim 10; wherein each of the guide slots of the rotor has a base section whose width is greater than the width of the vanes.
 18. The vane cell pump according to claim 10; wherein the base sections of the guide slots are rounded. 